DELAY
OF THE DAY

Ariane 5:
Anomaly detected, launch delayed

And here is the result of the Ariane 502
qualification assessment meeting I mentioned yesterday: the second
launch of the new Ariane 5 rocket will not take place on
October 28 as planned.

The French and European Space Agencies, CNES and ESA, said in a
joint statement that "An anomaly has been identified on the
Ariane launchers for flights 503 and 504 currently undergoing
integration at Aerospatiale, Les Mureaux, France. The items concerned
are the mountings of the Vulcain engine supply lines. It has
therefore been decided to check the same items on the 502 launcher."

That will take some time, and so a new target launch date will be
set during the course of next week. It is currently estimated that
the delay will be a few days to a week. "The other actions under
way have given satisfactory results," CNES and ESA said.

BUSINESS

Some
kind of take-over

Yesterday I reported about speculations of an
Internet news service that said "the most logical buyout has yet
to come: A Hughes Electronics takeover of even more troubled AT&T."

Funny  the Los Angeles Times today reports that "AT &
T Corp. is expected to announce Monday that Los Angeles aerospace
executive C. Michael Armstrong of Hughes Electronics Corp. will
become its chief executive." Is that some kind of take-over,
too?

ONLINE

Wired's
trip to space

Over the past few months, Sat-ND has
deliberately been trying to confuse you by reporting on a plethora of
new satellite systems. Wired will de-confuse you. Will they?

Called Teledesic, Celestri, SkyBridge, Globalstar etc., they'll
use different orbits and different technology. Their least common
denominator is the provision of all kinds or wireless communications
services such as Teledesic's "Internet in the sky."

Over the past four days, several interesting articles were
published, which also cover related topics such as rivalling systems,
satellite glitches, upcoming launch service providers, and space
junk.

BONUS
TRACK

Wired
or weird?

Wired describes Teledesic (in which
billionaires Bill Gates and Craig McCaw hold a 30.1 percent stake
respectively) as the upcoming major player of the satellite business:
"the company is dictating the course this new global
communications business will follow  even before Teledesic
launches its first satellite." True? Let's see.

Technical
facts

First of all, ask yourself the question why Teledesic has to
launch the record number of 266 satellites to get the complete system
up and running (originally, thrice as many were planned before
Boeing, Teledesic prime contractor and 10-percent shareholder, came
up with a better solution.) No competitor needs either that vast
number of spacecraft or the trifle of US$9 billion to build 'em and
get 'em all up.

The enormous amount satellites needed for the Teledesic system
arises from technical parameters such as the Low Earth orbit (LEO)
and the frequency range used. Teledesic will utilise the Ka-band,
meaning that uplink will take place in the range of 30 GHz, downlink
at 20 GHz simply because that's where sufficient adjacent chunks of
the frequency spectrum were still available for licensing a broadband
service.

Low
orbits, high frequencies

Even a Low Earth orbit does not exclude the influence of the
atmosphere that tends to distort and diminish signals sent and
received at such high frequencies. As a consequence, any signal will
have to take the shortest path to a ground station in order to be
received properly.

This is only the case when a satellite is visible at a high
elevation angle, which means it's almost directly overhead  but
for each satellite, that's the case for just a short period of time.
What's more, the Teledesic system layout calls for two
satellites accessible for any user within the system's reach at any
time.

"By being first to the punch, Teledesic has virtual reign
over 500 MHz of Ka-band spectrum worldwide," says Wired 
true, but exactly because of that they also have to set up the
largest satellite fleet ever at a record cost of US$9 billion. To my
knowledge, the whole system still has to be financed somehow.

Besides, more advanced satellite systems utilising the Ka-band
will rely on combinations of LEO and geostationary Earth orbits
(GEO.) Teledesic propaganda to the effect that GEO satellites would
be incapable of providing fast access to the World Wide Web, let
alone other high-speed multimedia applications, has meanwhile been
proven wrong.

Smart
Marketing

On the other hand, Wired is absolutely right about one thing:
Teledisc took some crucial regulatory hurdles during the past few
years. The project was, for instance, strongly opposed by European
governments at the International Telecommunications Unions (ITU) who
feared the United States would dominate the market for satellite
personal communications systems. The World Radio Conference (WRC)
nonetheless allocated frequencies to Teledesic because the company
had declared the developing countries a main target. Of course, those
countries voted in favour of Teledesic. Back then, Teledesic chairman
Russell Daggatt commented "We were betting the company on a
vote. Good thing we won."

This trick is nothing new  Iridium performed it, too. Once
they had received the international licences they needed, they turned
their main attention to wealthy businessmen and travellers in the
industrialised countries' densely populated areas instead.

Total and equal coverage of all countries is not exactly in
accordance with Teledesic's technical specifications anyway. They
call for a link availability of 99.9 percent over most of the United
States but just a 24-hour seamless coverage to over 95 percent of the
Earth's surface  whatever that may mean in real service
availability figures outside the U.S.

Other
problems

From the beginning of its operation, the Teledesic satellite fleet
will include a number of active in-orbit spares that amounts to ten
percent of the active fleet. They will be used to repair the network
whenever another satellite fails and has to be removed.

The fact that there will be such a large-scale redundancy has led
critics to argue that Teledesic actually expects its satellites to
drop out prematurely at a 10 percent rate. They may not have noticed
that even for geostationary broadcast satellites it isn't unusual to
carry a similar percentage of on-board spare transponders nowadays.
Owing to the very nature of the Teledesic project, it's impossible to
provide too much on-board redundancy, though.

Teledesic president Russell Daggatt said he expects a three
percent failure rate within the system per year, but even that will
still result in a quite respectable annual launch rate of replacement
satellites.

Conclusion

Still true: "It could end up a catastrophic failure or a
heroic success, or merge with another satellite scheme, or quietly
disappear."